Draining/Flushing LT1 Coolant System
 

Hi,
I just finished replacing the WP on my 92 LT1 and want to flush the entire coolant system.
Where are the block drain plugs/knock sensors located? Are they accessible from the top or the bottom of the car?
Will they brake loose easily or is their a chance of breaking them off in the block?
Thanks,
92WhiteVetteGuy
:cheers::cheers::cheers:

well you do have most of it out already if you replaced the W/p.
Did you install a drain in the weep hole.

Knock sensors are on both sides in the block.
On my 92 they have shields over them so the sensors aren't visible until you remove the shields.

You'll need to get under the car to remove the knock sensors, they're just above the oil pan on the block.

Will do with a drain hose.
:cheers::cheers::cheers:

I will take picks when I do mine,I will be working on it all week.
I think I'm gona wait till I get all new hoses before putting it back together.

Next time, remove your thermostat, open the radiator pitcock, then use a 6.0 hp (or higher) ShopVac with reverse thrust/blower capability and BLOW the air out using forced air.

You don't have to remove the knock sensors this way, plus it evacuates the entire system, heater core and all. :thumbs:

Been there done that + i agree %100

Old Jedi mechanic's trick. Work smarter, not harder, I always say. ;)

Hate to say this but the $5.00 flush kit they sell at parts stores dont work to bad. just tee the fitting in hook up water remove lower hose and let it run. not professional but removes a lot of crap

:iagree: just make sure to burp the system when done.

No worries. I often use the flush kits to break up mineral deposits and other contaminants, PLUS the ShopVac technique. Still don't have to remove the knock sensors, just the thermostat.

I always like to inspect/test thermostats when I do cooling system flush-n-fills anyhow. Annual maintenance item.

This sounds interesting, I would love to flush the coolant system without removing the knock sensors - is there a detailled sescription / video somewhere? I have both a strong ShopVac and a compressor, have an LT1 with unknown coolant in it that should not be re-used. I would like to flush in both directions, if possible.

where do u blow from. the t stat housing? rad cap? take t stat out and bolt housing back together?

Good question, I'll be doing this after Christmas so an answer would be most appreciated. Thanks for the help

Shop vac worked great. Sucked out all my coolant. Only 55,000 miles. Coolant was nice and clear orange. New water pump and wires. New plugs also. Real PIA job Wires go behind the air pump. Took the inner fender skirt off gave good visibility. Old wire were decent probably did not need new ones. I can see why the dealer wanted $$$$ to do the job.

I think you were supposed to BLOW the coolant out with the shopvac not suck it. This will help "push out" the gunk in the block/knock sensors. I have access to my block (rebuild) and I removed the knock sensors to empty the cooling system, some real crap that I would prefer come out of the block vs pushing it through the cooling system

I know this is an old thread but I would like to try the shop vac blowing system. I see take out the thermostat. Do you blow where the thermostat sits? Thank you very much, Dan

I have found a description on the net but I never trust them. It said to take out the thermostat but bolt it back up with the gasket. Remove both radiator hoses. Blow from the top and everything comes out the bottom hose. Can an expert please confirm this is correct? Thanks again, Dan